1. Field of the Invention
This invention relates to beverage brewers and in particular to beverage brewers having a hot water holding tank with means for preventing post-brewing drip therein.
2. Description of the Prior Art
In Harvey R. Karlen et al U.S. Pat. No. 2,869,760, owned by the assignee hereof, a hot water dispenser is shown in one form to include an aspirator providing an expansion space in a reservoir housing as a function of the liquid flow through the apparatus from a source of liquid to an outlet. The aspirator utilizes a venturi means which communicates with the reservoir expansion space so as to permit liquid to expand from the main tank into the evacuated reservoir space when the liquid is heated in the tank. Thus, as disclosed in said Karlen et al patent, the device is intended to prevent dripping of heated liquid from the tank outlet which would otherwise occur as a result of such expansion as in the absence of such an expansion space means, the liquid level, upon termination of the liquid delivery, would be at the level of the outlet so that subsequent expansion would cause a dripping of the expanding liquid outwardly from the outlet.
The use of aspirator control in connection with the automatic provision of an auxiliary collection space in a reservoir chamber is disclosed in William Kelly U.S. Pat. No. 1,216,815, wherein an aspirator is associated with a drain receptacle to permit water in the outlet pipe above the ground level to fall back into the drain receptacle upon termination of delivery of water through the pipe system in which the venturi-type aspirator is provided.
In U.S. Pat. No. 2,691,465 of Gardner Royce, a nondrip nozzle is provided in association with a liquid tank for accommodating the rise of liquid level due to thermal expansion of liquid in the tank so as to prevent escape of fluid through the nozzle as a result of such expansion. In the Royce nozzle, a venturi aspirator is provided as an integral portion of a reservoir chamber means. The delivery duct comprises an integral extension of the venturi aspirator and the entire nozzle is secured to an outlet pipe extending from the top cylinder head.
More recently, such aspirators have been used in hot water heaters such as for providing hot water from a pressure source, such as a domestic water supply system. Illustratively, in U.S. Pat. No. 2,903,551 of Harry C. Fischer, an aspirator is provided utilizing a tube having a closed bottom with a discharge pipe provided with a port opening into the tube.
U.S. Pat. No. 3,202,321 of Arthur B. Homeyer utilizes an aspirator-type dispenser in combination with a cap for controlling flow of the hot water through the device. In U.S. Pat. No. 3,642,176 of Richard C. Dreibelbis et al, a similar aspirator-type dispenser is provided with a hot water storage tank and a lever operating the control valve.